The only baby Pokémon introduced alongside their evolutions are Togepi and Riolu. To achieve evolution, many require maximized friendship. Others will evolve by level up, but as the generations passed more complex methods of evolution were introduced.

In the games, the only way to obtain most baby Pokémon is through breeding. On occasion, non-player characters will give the player an Egg containing a baby Pokémon, and this Pokémon typically cannot be obtained in any other method, except for breeding. Generation III introduced the first baby Pokémon able to be caught in the wild: Wynaut on Mirage Island. In Generation IV, many other baby Pokémon were also available in the wild. Players may still find it preferable to breed though, for the benefit of Egg moves (as many baby Pokémon have very limited movepools).

All baby Pokémon are unable to breed unless they evolve into one of their higher forms, and are all in the Undiscovered Egg Group. This is presumably due to their infantile state.

From Generation III on, most new baby Pokémon can only be obtained by making the parent in their evolutionary line hold a specific Incense before breeding, explaining why parent Pokémon available in previous generations were unable to produce these Eggs in those generations. For example, Marill, who was introduced in Generation II, could not produce Azurill Eggs until the introduction of the Sea Incense in Generation III.

From Generation VI on, baby Pokémon caught in the wild are guaranteed to have three random IVs of 31 by their inclusion in the Undiscovered Egg Group.

In the anime

All baby Pokémon have appeared in the anime so far, with some belonging to main characters. While most of them appear in the Pikachu Shorts regularly, all have had major appearances in the anime. In some cases, other newborn Pokémon are called baby Pokémon as well.

Baby Pokémon usually have childish personalities, but some begin to show signs of maturity after gaining experience or evolving, such as when Brock's Bonsly gave up bottle-feeding. However, Paul's Elekid was shown to have inherited his harsh personality. This is not limited to owned Pokémon, as Where No Togepi Has Gone Before! portrays a wild Togepi with mischievous intentions.

In the TCG

Baby PokémonCards listed with a blue background are only legal to use in the current Expanded format.Cards listed with a silver background are legal to use in both the current Standard and Expanded formats.

Of all post-Generation II baby Pokémon, only Azurill and Munchlax evolve by friendship alone (not requiring a certain time of day). In the anime, these two baby Pokémon are owned by two of Ash Ketchum's previous traveling companions, Misty and May.

All baby Pokémon that were introduced in Generation II that evolve by friendship can evolve further using evolutionary stones.

May, James, and Brock got their baby Pokémon (Munchlax, Mime Jr., and Bonsly respectively) following the pattern of premiering in a movie and then being captured by one of the main characters. In all cases, the premiered Pokémon is not the same character as the one caught, just the same species. In some cases, this may be a result of the writers deciding a Pokémon works well with the group after they are shown together. Munchlax came after Destiny Deoxys and Mime Jr. and Bonsly came after Lucario and the Mystery of Mew.